High-resolution electrophoretic procedures for the identification of five Eimeria species from chickens, and detection of population variation

To overcome limitations of conventional approaches for the identification o f Eimeria species of chickens, we have established high resolution electrop horetic procedures using genetic markers in ribosomal DNA. The first and se cond internal transcribed spacer (ITS-1 and ITS-2) regions of ribosomal DNA were amplified by polymerase chain reaction (PCR) from genomic DNA samples representing five species of Eimeria (E. acervulina, E. brunetti, E. maxim a, E, necatrix and E. tenella), denatured and then subjected to denaturing polyacrylamide gel electrophoresis (D-PAGE) or single-strand conformation p olymorphism (SSCP) analysis. Differences in D-PAGE profiles for both the IT S-1 and ITS-2 fragments (combined with an apparent lack of variation within individual species) enabled the unequivocal identification of the five spe cies, and SSCP allowed the detection of population variation between some i solates representing E. acervulina, which remained undetected by D-PAGE. Th e establishment of these approaches has important implications for controll ing the purity of laboratory lines of Eimeria, for diagnosis and for studyi ng the epidemiology of coccidiosis.